396 SCIENTIFIC THOUGHT IN THE NINETEENTH CENTURY. 



applications of science. Fitly, then, our thoughts to-day dwell, not 

 upon the vast progress of the useful arts, but upon the progress of 

 pure science. Not the economic and the industrial, l)ut the intellectual 

 history of our century claims our attention. 



I do not propose, in the few moments allotted to me this afternoon, 

 to give an inventory of the important scientific discoveries of the 

 nineteenth century. The time would not suffice therefor, even were 

 my knowledge of the various sciences sufficiently encyclopedic to 

 justify me in the attempt. I wish rather to call your attention to a 

 single broad, general aspect of the intellectual history of our age. I 

 wish to remind you in how large a degree those general ideas which 

 make the distinction between the unscientific and the scientific view of 

 nature have been the work of the nineteenth century. 



The first of these ideas is the extension of the universe in space. 

 The unscientific mind looks upon the celestial l)()dies as mere append- 

 ages to the earth, relatively of small size, and at no very great distance. 

 The scientific mind beholds the stellar universe stretching away be3^ond 

 measured distances whose numerical expression transcends all power 

 of imagination, into immeasurable immensities. 



The second of these ideas is the extension of the 'universe in time. 

 To the unscientific mind the universe has no history. Since it began 

 to exist it has existed substantialh' in its present condition. Among 

 Christian peoples, until the belief was corrected by science, the 

 He])rew tradition of a creative week six thousand years ago was gene- 

 rally accepted as a historic fact. If, on the other hand, unscientific 

 minds not possessed of any supposed revelation in regard to the date 

 of the world's origin, thought of the universe as eternal, that eternit}'' 

 was still conceived as an eternity of unhistoric monotony. The scien- 

 tific mind sees in the present condition of the universe the monuments 

 of a long history of progress. 



The third of these ideas is the unitv of the universe To the unsci- 

 entific mind the universe is a chaos. To the scientific mind it becomes 

 a cosmos. To the unscientific mind the processes of nature seem to be 

 the result of forces mutually independent and often discordant. 

 Polytheism in religion is the natural counterpart of the unscientific 

 view of the universe. To the scientific mind the boundless complexity 

 of the universe is dominated by a supreme unity. One system of 

 law, intelligible, formulable, pervades the universe, through all its 

 measureless extension in space and time. The student of science may 

 be theist or pantheist, atheist or agnostic; polytheist he can never be. 



"W hat then, let us a.sk ourselves, has been the contribution of our 

 century to the development of these three ideas which characterize 

 the scientific view of nature; the spatial extension of the universe, the 

 historic extension of the universe, and the unity of the universe. 



The development of the idea of the extension of the universe in 



